Jacks define female receptacle connectors having a non-conductive housing and electrical conductive terminals therein. The jack typically is mounted to a circuit board, panel or the like, with the terminals in the jack being electrically connected to conductive areas on the circuit board or to a cable. The jack is mateable with a male plug connector which also has a nonconductive housing and a corresponding number of electrically conductive terminals. The plug frequently will be attached to a cable having a plurality of electrically conductive leads which are respectively connected to the terminals in the plug. The cable leading to the plug may be a round cable or a flat flexible cable depending upon the particular application. This combination of jacks and mateable plugs, constituting a modular jack/plug (or mod-jack)assembly, is used in many electrical devices, with broad applications being found in the computer and telecommunications industries. Currently, 4, 6, and 8 circuit mod-jack assemblies are manufactured. 10 circuit assemblies may be developed in the future.
Mating between the plug and jack is generally effected by insertion of the plug into a plug-receiving cavity in the receptacle housing. Locating ribs may be provided on the body of the plug to aid in positioning of the plug with respect to the receptacle housing prior to and during plug insertion. A latching system may be provided for maintaining the plug and receptacle in a mated state once the plug has been inserted. As an indication to a user that the plug has been fully inserted into the jack, the latching system is generally configured to produce an audible clicking sound when the plug is fully inserted.
A problem exists with the current mod-jack assemblies in that undersized plugs, having a width smaller than that which a given plug-receiving cavity is designed to receive, can be inserted into a plug-receiving cavity of a receptacle housing. When an undersized plug is inserted into a plug-receiving cavity designed to receive a plug having a width greater than that of the undersized plug, the locating ribs on the plug body will align with terminals in the plug receiving cavity, damaging the terminals. Also, the connection between the larger-width jack and the smaller-width plug may be incompatible, even though the user hears an audible click indicating that the plug is fully inserted.
One method of addressing this problem is provided in Jones et al., U.S. Pat. No. 4,764,129. In Jones et al. '129, narrower plugs in a series of electrical connector assemblies are prevented from insertion into wider sockets in the series by varying the height of the plugs and sockets and/or varying the cross-sectional dimensions of a key and keyway provided on the plugs and sockets. A problem with this approach is that provision for numerous variations in the configurations of the plug and receptacle bodies greatly increases the complexity and expense of tooling, such as molds and assembly fixtures.